creating stub functions to determine how much money is spending on the car

I need to determine how much money is spending on the car. Specifically, to know how much the persons spends per day having the car sit in her driveway and how much spends per mile driving it. While working through this problem, came up with the following structure chart:

structure chart

I need to create stub functions for all the functions. In other words, write a program to stub out every function represented in the above structure chart. If a function calls another function (ex: getPeriodicCost() calls promptParking()), then make sure that function call is in the stub. Finally, make sure all the parameters and return values from the structure chart are represented in the stub functions.